Analog-to-digital converters (ADCs) are utilized in a variety of electronic devices and systems to transform an analog signal to a digital signal. One ADC architecture commonly used is the delta-sigma ADC. The differentiating aspects of the delta-sigma ADCs include the use of oversampling in conjunction with decimation filtering and quantization noise shaping. Advantageous characteristics of the delta-sigma ADC include high resolution and high stability. Due to these characteristics, delta-sigma ADCs are frequently chosen for use in audio systems, such as hearing devices, microphones, and the like.
Due to the low operating voltage of many devices which employ the delta-sigma ADCs, the signal-to-noise ratio (SNR) performance and dynamic range can be greatly diminished. The dynamic range of a system may be described as the range of amplitudes between a noise component of the system and the onset of clipping (the level at which the power supply is no longer adequate to provide larger waveforms), while the SNR may be described as the ratio of a signal component (at some arbitrary level) to a noise component.
Many audio applications require enhanced SNR performance and dynamic range while maintaining particular design specifications, such as the operating voltage, oversampling ratio, and total area of the chip size.
Delta-sigma ADCs commonly employ a digital signal processor to correct over-amplified signals, remove noise components, and the like. Digital signal processors typically required to process a wide voltage range, comprise multiple circuits that include numerous components, and generally occupy a large area on the chip.